/*
 * cpuidle.h - a generic framework for CPU idle power management
 *
 * (C) 2007 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
 *          Shaohua Li <shaohua.li@intel.com>
 *          Adam Belay <abelay@novell.com>
 *
 * This code is licenced under the GPL.
 */

#ifndef _LINUX_CPUIDLE_H
#define _LINUX_CPUIDLE_H

#include <linux/percpu.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/kobject.h>
#include <linux/completion.h>

#define CPUIDLE_STATE_MAX	8
#define CPUIDLE_NAME_LEN	16
#define CPUIDLE_DESC_LEN	32

struct cpuidle_device;

/****************************
 * CPUIDLE DEVICE INTERFACE *
 ****************************/

struct cpuidle_state {
	char name[CPUIDLE_NAME_LEN];
	char desc[CPUIDLE_DESC_LEN];
	void *driver_data;

	unsigned int flags;
	unsigned int exit_latency;	/* in US */
	unsigned int power_usage;	/* in mW */
	unsigned int target_residency;	/* in US */

	unsigned long long usage;
	unsigned long long time;	/* in US */

	int (*enter) (struct cpuidle_device * dev,
		      struct cpuidle_state * state);
};

/* Idle State Flags */
#define CPUIDLE_FLAG_TIME_VALID	(0x01)	/* is residency time measurable? */
#define CPUIDLE_FLAG_CHECK_BM	(0x02)	/* BM activity will exit state */
#define CPUIDLE_FLAG_POLL	(0x10)	/* no latency, no savings */
#define CPUIDLE_FLAG_SHALLOW	(0x20)	/* low latency, minimal savings */
#define CPUIDLE_FLAG_BALANCED	(0x40)	/* medium latency, moderate savings */
#define CPUIDLE_FLAG_DEEP	(0x80)	/* high latency, large savings */

#define CPUIDLE_DRIVER_FLAGS_MASK (0xFFFF0000)

/**
 * cpuidle_get_statedata - retrieves private driver state data
 * @state: the state
 */
static inline void *cpuidle_get_statedata(struct cpuidle_state *state)
{
	return state->driver_data;
}

/**
 * cpuidle_set_statedata - stores private driver state data
 * @state: the state
 * @data: the private data
 */
static inline void
cpuidle_set_statedata(struct cpuidle_state *state, void *data)
{
	state->driver_data = data;
}

struct cpuidle_state_kobj {
	struct cpuidle_state *state;
	struct completion kobj_unregister;
	struct kobject kobj;
};

struct cpuidle_device {
	unsigned int registered:1;
	unsigned int enabled:1;
	unsigned int cpu;

	int last_residency;
	int state_count;
	struct cpuidle_state states[CPUIDLE_STATE_MAX];
	struct cpuidle_state_kobj *kobjs[CPUIDLE_STATE_MAX];
	struct cpuidle_state *last_state;

	struct list_head device_list;
	struct kobject kobj;
	struct completion kobj_unregister;
	void *governor_data;
	struct cpuidle_state *safe_state;
};

DECLARE_PER_CPU(struct cpuidle_device *, cpuidle_devices);

/**
 * cpuidle_get_last_residency - retrieves the last state's residency time
 * @dev: the target CPU
 *
 * NOTE: this value is invalid if CPUIDLE_FLAG_TIME_VALID isn't set
 */
static inline int cpuidle_get_last_residency(struct cpuidle_device *dev)
{
	return dev->last_residency;
}

/****************************
 * CPUIDLE DRIVER INTERFACE *
 ****************************/

struct cpuidle_driver {
	char name[CPUIDLE_NAME_LEN];
	struct module *owner;
};

#ifdef CONFIG_CPU_IDLE

extern int cpuidle_register_driver(struct cpuidle_driver *drv);
extern void cpuidle_unregister_driver(struct cpuidle_driver *drv);
extern int cpuidle_register_device(struct cpuidle_device *dev);
extern void cpuidle_unregister_device(struct cpuidle_device *dev);

extern void cpuidle_pause_and_lock(void);
extern void cpuidle_resume_and_unlock(void);
extern int cpuidle_enable_device(struct cpuidle_device *dev);
extern void cpuidle_disable_device(struct cpuidle_device *dev);

#else

static inline int cpuidle_register_driver(struct cpuidle_driver *drv)
{
	return 0;
}

static inline void cpuidle_unregister_driver(struct cpuidle_driver *drv)
{
}

static inline int cpuidle_register_device(struct cpuidle_device *dev)
{
	return 0;
}

static inline void cpuidle_unregister_device(struct cpuidle_device *dev)
{
}

static inline void cpuidle_pause_and_lock(void)
{
}

static inline void cpuidle_resume_and_unlock(void)
{
}

static inline int cpuidle_enable_device(struct cpuidle_device *dev)
{
	return 0;
}

static inline void cpuidle_disable_device(struct cpuidle_device *dev)
{
}

#endif

/******************************
 * CPUIDLE GOVERNOR INTERFACE *
 ******************************/

struct cpuidle_governor {
	char name[CPUIDLE_NAME_LEN];
	struct list_head governor_list;
	unsigned int rating;

	int (*enable) (struct cpuidle_device * dev);
	void (*disable) (struct cpuidle_device * dev);

	int (*select) (struct cpuidle_device * dev);
	void (*reflect) (struct cpuidle_device * dev);

	struct module *owner;
};

#ifdef CONFIG_CPU_IDLE

extern int cpuidle_register_governor(struct cpuidle_governor *gov);
extern void cpuidle_unregister_governor(struct cpuidle_governor *gov);

#else

static inline int cpuidle_register_governor(struct cpuidle_governor *gov)
{
	return 0;
}

static inline void cpuidle_unregister_governor(struct cpuidle_governor *gov)
{
}

#endif

#ifdef CONFIG_ARCH_HAS_CPU_RELAX
#define CPUIDLE_DRIVER_STATE_START	1
#else
#define CPUIDLE_DRIVER_STATE_START	0
#endif

#endif /* _LINUX_CPUIDLE_H */
